A couple of ideas:
1. Did you click on the plane and accidentally activate "Hide feature"?
2. F5 > on the General tab scroll down to near the bottom > check "Display Outline of Plane".
A couple of ideas:
1. Did you click on the plane and accidentally activate "Hide feature"?
2. F5 > on the General tab scroll down to near the bottom > check "Display Outline of Plane".